iavf: Fix double free in iavf_reset_task

iavf: Fix double free in iavf_reset_task

Fix double free possibility in iavf_disable_vf, as crit_lock is
freed in caller, iavf_reset_task. Add kernel-doc for iavf_disable_vf.
Remove mutex_unlock in iavf_disable_vf.
Without this patch there is double free scenario, when calling
iavf_reset_task.

Fixes: c4569c809d75 ("iavf: Fix deadlock in iavf_reset_task")
Signed-off-by: Przemyslaw Patynowski <przemyslawx.patynowski@intel.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>